Buggy code:
public class XMPPGroupChatSOContainer extends ClientSOContainer implements IChatRoomContainer { public static final String XMPP_GROUPCHAT_DELEGATE_ID = ( XMPPClientSOContainer . class . getName ( ) ) + ".xmppgroupchathandler" ; XMPPConnection xmppconnection ; ID sharedObjectID ; XMPPGroupChatSharedObject delegate ; MultiUserChat multiuserchat ; ISharedObjectContainerConfig config ; Namespace usernamespace = null ; public XMPPGroupChatSOContainer ( ISharedObjectContainerConfig config , ISynchAsynchConnection conn , XMPPConnection xmppconn , Namespace usernamespace ) throws IDCreateException { } public XMPPGroupChatSOContainer ( ISynchAsynchConnection conn , XMPPConnection xmppconn , Namespace usernamespace ) throws IDCreateException { } public void dispose ( ) { } protected void sendMessage ( ContainerMessage data ) throws IOException { } protected void handleChatMessage ( Message mess ) throws IOException { } protected boolean verifyToIDForSharedObjectMessage ( ID toID ) { } protected void handleContainerMessage ( ContainerMessage mess ) throws IOException { } protected void handleIQMessage ( IQ mess ) throws IOException { } protected void handlePresenceMessage ( Presence mess ) throws IOException { } protected void handleChatMembershipEvent ( String from , boolean add ) { } protected void handleXMPPMessage ( Packet aPacket ) { } protected void initializeSharedObject ( ) throws IDCreateException { } protected void addSharedObjectToContainer ( ID remote ) throws SharedObjectAddException { } protected void cleanUpConnectFail ( ) { } public Namespace getConnectNamespace ( ) { } public void connect ( ID remote , IConnectContext connectContext ) throws ContainerConnectException { } public void disconnect ( ) { ID groupID = getConnectedID ( ) ; fireContainerEvent ( new org . eclipse . ecf . core . events . ContainerDisconnectingEvent ( this . getID ( ) , groupID ) ) ; synchronized ( getConnectLock ( ) ) { if ( isConnected ( ) ) { try { multiuserchat . leave ( ) ; } catch ( Exception e ) { <START_BUG> dumpStack ( "Exception<seq2seq4repair_space>in<seq2seq4repair_space>multi<seq2seq4repair_space>user<seq2seq4repair_space>chat.leave" , e ) ; <END_BUG> } } connectionState = DISCONNECTED ; this . xmppconnection = null ; remoteServerID = null ; } fireContainerEvent ( new org . eclipse . ecf . core . events . ContainerDisconnectedEvent ( this . getID ( ) , groupID ) ) ; } protected SOContext createSharedObjectContext ( SOConfig soconfig , IQueueEnqueue queue ) { } protected ID createChatRoomID ( String groupName ) throws IDCreateException { } protected ISynchAsynchConnection createConnection ( ID remoteSpace , Object data ) throws ConnectionCreateException { } public void addMessageListener ( IMessageListener listener ) { } public void removeMessageListener ( IMessageListener msgListener ) { } public IChatMessageSender getChatMessageSender ( ) { } public void connect ( String groupName ) throws ContainerConnectException { } public void addChatParticipantListener ( IChatParticipantListener participantListener ) { } public void removeChatParticipantListener ( IChatParticipantListener participantListener ) { } }

Fix:
traceStack ( "Exception<seq2seq4repair_space>in<seq2seq4repair_space>multi<seq2seq4repair_space>user<seq2seq4repair_space>chat.leave" , e ) ;